Objective/Hypothesis: Recent work from Dr. Fink's laboratory suggests that IME4 (early inducer of meiosis gene) acts as a switch in determining whether cells will undergo meiosis or filament and produces an antisense transcript under a/alpha control. Because of the connection between IME4 and the filamentation pathway in S. cerevisiae, and since there is both an IME4 homolog and MTL a1/alpha2 binding sites in the gene regulatory regions of C. albicans' IME4, my hypothesis is that a1/alpha2 plays a role in regulating IME4 antisense and sense expression and that IME4 regulation in S. cerevisiae is conserved in C. albicans. This regulatory mechanism is likely to have potential implications in the C. albicans' pathogenically important morphological switch from yeast to filamentous growth. Specific Aims: I. Determine the role and regulatory mechanism of IME4 in cell-fate determination in S. cerevisiae. II. Elucidate the function and mechanism of regulation of C. albicans' IME4.